The disposal of scrap or used tires poses a serious threat to our environment. Unlike other waste products, tires do not readily break down in air or soil. It has been estimated that three billion tires have been discarded into U.S. dumps and land fills. Often, whole tires are simply piled onto vacant space within the dump, creating an eyesore. There, the inner cavities of these tires collect rain water and provide a breeding ground for mosquitoes. As a further hazard, the discarded tires in these piles are often worn to the point where their reinforcing wires are exposed. The exposed wire can injure persons handling the tires or children that attempt to climb the piles.
In other instances, the tires are buried. However, chemical reactions between the tires, soil, and air trapped in the inner cavities can create sufficient heat to ignite the tires, creating a dangerous fire hazard. For these reasons, there have been many attempts to recycle tires into useful products.
Attempts to recycle and reuse tires have focused on several techniques, including reclaiming the rubber from the tires through chemical processes, ultrasonic devulcanization, and grinding. Thereafter, the reclaimed rubber is mixed with other components during subsequent processing. However, each of these reclaiming techniques requires that the non-rubber materials, such as the metal belts used in belted tires, be removed from the tires before processing can begin. Consequently, each of these reclaiming techniques can be complicated and costly. Consequently, it is desirable to recycle and reuse tires without separating the rubber from the non-rubber materials.
U.S. Pat. No. 6,583,211 describes a process where pieces of cut tires are combined with thermosetting material, thermoplastic material, or mixtures thereof, in a mold to produce a composite material having high rigidity. For example, the tire pieces are mixed with liquified thermosetting and/or thermoplastic materials to form a flowable melt of composite material which is subsequently molded into a desired shape.
Because such tire pieces damage extrusion and injection molding dies when the flowable melt is flowing therethrough, fixed-size molds have been necessary to shape the composite material. These fixed-size molds are closed upon filling to allow the material therein to set. As the material sets, significant pressures are developed inside the mold. These fixed-size molds are able to form the composite material into inexpensive, useful articles. But as their name suggests, these fixed-size molds are fixed in shape and volume, and new molds must be provided to produce differently sized articles
Consequently, if the composite material is used in making an elongate article such as an elongate beam, a mold must be provided that is at least as long as the desired length of the elongate beam. For example, if the mold is longer than the desired length of the elongate beam, then the resulting elongate beam can be cut to length. However, if the mold is shorter than the desired length of the elongate beam, then a new mold must be provided to accommodate the desired length of the elongate beam. Either way, material may be wasted or a new mold must provided. Moreover, articles of greater size produce higher pressures within the fixed-size molds, to the point that, large articles (including elongate beams) cannot be contained without causing such fixed-size molds to break.
As such, there is a need for molding process used to mold elongate articles formed from a composite materials including tire pieces that overcomes the deficiencies of molding processes using fixed-size molds.